An organic electroluminescence device using an organic substance (hereinafter, electroluminescence may be abbreviated as EL) has a potential to find use in an application as a thin, inexpensive, large-screen, full-color display device, and a large number of such devices have been developed. In general, an organic EL device is a spontaneous light-emitting device utilizing a principle in which an electric field is applied so that an organic substance emits light owing to the recombination energy between a hole injected from an anode and an electron injected from a cathode.
A conventional organic EL device has a higher driving voltage, a lower emission luminance, and a lower efficiency of light emission that those of an inorganic light-emitting diode. Although a recent organic EL device is gradually improved, an increased emission luminance and an increased efficiency of light emission at a low voltage have been requested.
For example, a blue light-emitting device using a benzimidazole derivative as an electron-transmitting material has been disclosed as means for emitting light at a high emission luminance and a high efficiency of light emission at a low voltage (see, for example, Patent Document 1 below). In this invention, a compound represented by the following formula (a) is used as an electron-transmitting layer, so blue light emission having an emission luminance of 537 cd/m2 and a efficiency of light emission of 2.69 cd/A at a current density of 20 mA/m2 is obtained. In addition, a compound represented by the following formula (b) having a benzimidazole ring and an anthracene skeleton has been disclosed (see, for example, Patent Document 2 below). However, an organic EL device using any one of those compounds does not have a sufficient efficiency of light emission, so an additional improvement in efficiency of light emission has been desired.

Patent Document 1: JP-A-10-106749
Patent Document 2: WO 03/060956